The present invention relates to systems and methods for network communications. More particularly, the present invention relates to a timing interface module with daughter timing reference modules.
The increasing use and expansion of digital voice, TV and Internet services continue to apply pressure for increased bandwidth. In fact, even more bandwidth-intensive services are on the horizon. This increased demand means service providers need to add capacity to their networks as quickly as possible. Previously, that process required the integration of additional hardware or even the complete replacement of existing networks because a service provider's network typically only allows so much data traffic to travel through at any given time.
However, advancements in optical transport systems fully integrate additional bandwidth capability in easily expandable modules. Moreover, such advancements are allowing providers to increase the bandwidth available on their existing networks without extensive network redesign or reconfiguration. For example, rather than installing additional stand-alone hardware, an optical transport system may be used to integrate pure optical switching via wavelength selective switches, reconfigurable optical add-drop multiplexing, Ethernet switching, next-generation SONET/SDH add-drop multiplexers and dense wavelength division multiplexing (DWDM) into a single platform. Thus, traffic may be added or dropped into a DWDM network to easily increase bandwidth to offer HDTV, video-on-demand and high-speed Internet access.
A SONET multiplexer enables carriers to cost-effectively combine signals of multiple optical carrier levels onto one wavelength for transport. Further, SONET network equipment transports and/or multiplexes traffic that has originated from a variety of different clock sources. Thus, SONET requires timing sources to provide synchronization. External timing connections provide the timing signals to ensure synchronous accuracy of the network. In contrast, other types of networks do not require timing, e.g., Ethernet, ATM, SAN, etc. For example, legacy DWDM and other data systems do not have external timing connections.
It can be seen then that there is a need for a method and apparatus for providing external timing to systems for combining synchronous and data signals while complying with all relevant industry standards.